Effects of explant types and media salt strength on growth and secondary metabolite accumulation in adventitious roots of Periploca sepium Bunge

In order to study the capabilities of Periploca sepium adventitious root induction in different types of explants, we selected leaves, roots and stems with or without buds. The growth of adventitious roots and periplocin content in these roots were determined. In order to investigate the suitable media salt strength, we cultured the adventitious roots in different salt strength (0.25, 0.50, 1.0, 1.5, 2.0) of Murashige and Skoog (MS) media supplemented with 1 mg/l indole butyric acid (IBA) and 30 g/l sucrose. The results showed that both leaf and root explants were proven suitable for the adventitious root induction; however, the stems could hardly induce adventitious roots no matter whether the stems had buds or not. Further studies reported that adventitious root proliferation and periplocin production derived from root explants were higher than those derived from leaf explants. So the root explants were the optimum explants for adventitious root induction, growth and periplocin production. The salt strength experiment showed that with the increasing salt strength (1.0-2.0 MS), adventitious root growth decreased significantly, as well as periplocin content in comparison with lower (0.25-0.5 MS) salt strength media.